The present invention pertains generally to studs and more specifically to a threaded weld stud and a protective cap.
It is well known in the automotive industry to employ a metallic weld stud having an enlarged base and a shaft with a single thread. The traditional thread spirals around the shaft, in a continuous manner, at least fourteen times between the distal end of the shaft and the base. It is common to engage a nut with the threaded shaft so as to retain a component to the stud and vehicle body.
In one traditional application, an electrical eyelet is placed loosely over the shaft of a weld stud. A nut is then rotatably engaged with the threaded stud to secure the terminal. This is used to provide an electrical ground between the electrical terminal and the metal body panel of the vehicle. However, the engagement of this nut and threaded stud is prone to assembly difficulties, especially on a quickly moving vehicle assembly line. For example, nuts are often dropped or incorrectly aligned with the threads during engagement. Furthermore, the torque wrenches employed to drive the nuts are heavy and ungainly to move around in a tightly packaged engine compartment. Moreover, torque of the nut on the stud is often inconsistent leading to possible intermittent electrical connections.
A portion of a weld stud that will contact an electrical terminal must be clean in order to provide a suitable electrical current carrying path. This has proven difficult due to E-coating and subsequent painting of the panel after the stud is welded onto the panel. Thus, plastic protective caps have been placed over the threaded portion of the weld stud during the coating processes in the assembly plant. The protective cap is subsequently removed. However, the conventional caps are provided with an internal thread and an external hexagonal shape in order to allow for secure assembly onto the stud. A torsion wrench is often used to remove these caps from the stud after the painting process. The cap installation and removal process, and tools have also proven difficult to use, time-consuming and cumbersome.